Major news organizations were given a little advance notice that de Blasio planned to jet out to Iowa and on to South Carolina to stump in the hours after splashing the announcement on Good Morning America Thursday.

They agreed to respect a media embargo on the info.

But Fleisher had the gumption to check the Facebook page of the Truman Democratic Club in Sioux City, Iowa, where de Blasio was slated to speak. Sure enough, the club had posted the details of the appearance, which it said was designed to kick off the mayor’s White House bid.

So Fleisher did what any Millennial reporter would do: he tweeted it out.

Fleisher, whose father is a rabbi, quickly won a new round of plaudits from media big-wigs three times his age.

“It was exciting to watch it instantly get attention and trigger discussion,” he told The Washington Post about his de Blasio tweet.

He emphasized that he had finished his homework before scanning Facebook to score the de Blasio scoop.

He’s been fascinated by politics since he was 9 and launched the daily newsletter in 2012 after a story about him appeared in the St. Louis Dispatch. He grew in notoriety when The New York Times profiled him in 2017.